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Biology subjects

Garcia, H. H.

Publications and source records attributed to Garcia, H. H..

4 recordsLinked to original sources

Pericystic brain transcriptomics reveals molecular signatures of immune activation and neurovascular remodelling in viable and post-treatment porcine neurocysticercosis

Neurocysticercosis (NCC), the infection of the central nervous system by Taenia solium larvae, is a leading cause of acquired epilepsy in endemic regions. While viable cysticerci can persist asymptomatically for extended periods, their spontaneous or drug-induced degradation triggers marked perilesional inflammation and severe neurological symptoms. Despite well-documented histopathological characterisation of these lesion states, the host transcriptional programmes associated with viable parasite persistence and early post-treatment lesion disruption remain poorly understood. To address this gap, we performed the first bulk RNA sequencing of pericystic brain tissue using a physiologically relevant porcine model of NCC. Comparing uninfected controls (n = 3), infected untreated pigs with intact viable cysts (n = 6), and antiparasitic-treated pigs with disrupted cysts (n = 3), we identified distinct transcriptional signatures associated with each disease state. Viable infection was associated with broad transcriptional changes (461 upregulated and 175 downregulated genes), characterised by local immune activation alongside suppression of blood-brain barrier (BBB) remodelling, vascular, and neuronal signalling molecular signatures. The post-treatment state with confirmed BBB disruption was associated with a smaller but directionally distinct response (160 upregulated and 57 downregulated genes), marked by inflammatory signalling and increased expression of genes associated with endothelial activation, vascular regulation, and BBB-associated remodelling. Together, these findings suggest that, while immune engagement is a feature shared across both lesion states, the BBB-associated transcriptional axis shifts substantially following treatment. These results provide an exploratory transcriptomic framework for understanding parasite persistence, treatment-induced neuroinflammation, and neurovascular remodelling in NCC, and highlight candidate pathways and genes for future mechanistic investigation. Author SummaryNeurocysticercosis is a major cause of epilepsy in regions where Taenia solium is endemic. Brain cysts can remain viable for long periods with limited symptoms, but parasite degeneration, whether spontaneous or drug-induced, can trigger damaging neuroinflammation. In this study, we used RNA sequencing in a pig model that closely resembles human disease to characterise how brain tissue responds to viable cysts and to early treatment-induced cyst disruption. We found that viable infection was associated with local immune activation alongside reduced expression of genes involved in blood-brain barrier function. Following antiparasitic treatment, disrupted lesions showed an increased expression of genes linked to vascular and barrier remodelling. These findings suggest that the host transcriptional environment changes substantially after parasite disruption, and highlight molecular pathways that may contribute to neuroinflammation, blood-brain barrier changes, and neurological disease in NCC. As an exploratory first transcriptomic survey in this model, these results provide a candidate framework for future studies aimed at identifying biomarkers and adjunctive therapeutic targets in NCC.

genomics↗

Single-cell transcriptional dynamics in a living vertebrate

The ability to quantify transcriptional dynamics in individual cells via live imaging has revolutionized our understanding of gene regulation. However, such measurements are lacking in the context of vertebrate embryos. We addressed this deficit by applying MS2-MCP mRNA labeling to the quantification of transcription in zebrafish, a model vertebrate. We developed a platform of transgenic organisms, light sheet fluorescence microscopy, and optimized image analysis that enables visualization and quantification of MS2 reporters. With these tools, we obtained single-cell, real-time measurements of transcriptional dynamics of the segmentation clock. Our measurements challenge the traditional view of smooth clock oscillations and instead suggest a model of discrete transcriptional bursts that are organized in space and time. Together, these results highlight how measuring single-cell transcriptional activity in the context of vertebrate organisms can reveal unexpected features of gene regulation and how this data can fuel the dialogue between theory and experiment.

developmental biology↗

Decoding of YAP levels and dynamics by pluripotency factors

YAP is a transcriptional regulator that controls pluripotency, germ layer specification, and proliferation. Different subsets of YAP target genes are engaged in each physiological setting, but how YAP selectively regulates different effectors in different contexts is not known. Here we use optogenetics to investigate how the levels and dynamics of YAP activation control its pluripotency effectors Oct4 and Nanog. We observe different thresholds for repression of Oct4 and Nanog, enabling differential control of both genes through YAP levels. Pluripotency factors also decode YAP dynamics. Oct4 preferentially responds to oscillatory YAP inputs that mimic endogenous pulsatile YAP dynamics. Using single-cell live imaging of Oct4 transcription and computational-theoretical analysis of transcriptional regulation, we demonstrate that YAP dynamics are decoded by an adaptive change sensor that modulates Oct4 transcription burst frequency. Our results reveal how the levels and timing of YAP activation enable multiplexing of information transmission for key regulators of cellular differentiation and pluripotency.

cell biology↗

Assembly and phylogeographic analysis of novel Taenia solium mitochondrial genomes reveal further differentiation between and within Asian and African-American genotypes

BackgroundTaenia solium is a parasite that hampers human health, causing taeniasis and cysticercosis. The genetic variability in its mitochondrial genome is related to the geographical origin of the specimen. Two main genotypes have been identified: The Asian and the African-American. The geographic genetic variability is expected to cause different clinical manifestations. Thus, characterizing differences between and within genotypes is crucial for completing the epidemiology of T. solium diseases. Methods/Principal FindingsHere, two Peruvian (one complete and one partial; 7,811X and 42X of coverage, respectively) and one Mexican (complete, 3,395X) T. solium mitochondrial genomes were assembled using the Chinese reference. Variant calling with respect to the reference was performed. Thirteen SNPs that involved a change in the amino acid physicochemical nature were identified. Those were present in all the assembled genomes and might be linked to differences in aerobic respiration efficiency between Latin American (African-American) and Asian genotypes. Then, phylogeographic studies were conducted using Cytochrome C oxidase subunit I and cytochrome B from these genomes and other isolates. The analysis showed that Indonesian samples are the most ancient and related to the modern T. solium ancestor of the Asian genotype. Finally, a consistent subdivision of the African-American genotype into two subgroups was found. One subgroup relates to East African countries, while the other is West Africa. The East African linage suggests a previously unnoticed influence of the Indian Ocean trade in the genetic structure of Latin America T. solium. Conclusions/SignificanceOverall, this study reports novel mitochondrial genomes valuable for further studies. New Latin American SNPs were identified and suggest metabolic differences between parasites of the Asian and African-American genotypes. Moreover, the phylogeographic analysis revealed differences within each genotype that shed light on T. soliums historical spread. Overall, the results represent an important step in completing T. solium genetic epidemiology. Author SummaryTaenia solium is a human parasite that causes taeniasis and cysticercosis. Eradicated from developed countries, they are still a public health problem in developing nations. T. solium differences in the mitochondrial genetic material depend on its geographical origin. This is expected to cause different clinical manifestations. Despite the importance of genetics to the epidemiology of T. solium diseases, few efforts have been made to assemble and compare their genomes. We aimed to help fill this knowledge gap by assembling three mitochondrial genomes from Latin America and comparing them to the Chinese reference. Additionally, two genes from the Latin American genomes and from other isolates were employed to assess T. solium genetic distribution. We found thirteen mutations with respect to the Chinese genome present in all Latin American samples, which involved a change in the amino acid physicochemical nature. Those might be causing metabolic differences between Asian and Latin American parasites that could change their affinity to specific human tissues. Moreover, we determined that Indonesian samples are the most ancient and related to the modern T. solium ancestor. Finally, we identified a previously unnoticed influence of East African countries in T. solium phylogeny, with which our assembled genomes are closely related.

genetics↗